UPDATED: The a cappella competition improves 26 percent from its last premiere, two years ago.

UPDATE: Final returns see adjustments for many, with The Voice (3.5 adults) and Sleepy Hollow (2.2 adults) both improving by a tenth -- and ABC's The Great Christmas Light Flight (1.4 adults) shedding a significant four-tenths of a point with NFL preemptions taken into account.

Previously: The TV schedule is starting to get quiet for the holidays, though NBC did use Monday to relaunch singing competition The Sing Off. Averaging a 2.4 rating among adults 18-49, the series was up 26 percent from its third-season opener in 2011. The show had the obvious advantage of a lead-in from The Voice, steady with last Monday's 3.4 rating among adults 18-49. NBC averaged a 2.8 rating among adults 18-49 and 9.9 million viewers.

Fox saw Almost Human (1.8 adults) improve by one-tenth of a point at 8 p.m., with Sleepy Hollow (2.1 adults) dipping by the same measure. The network averaged a 2.0 rating with adults 18-49 and 6.3 million viewers.

ABC aired holiday specials and an encore of Castle to the tune of a 1.6 rating with adults 18-49 and 6.5 million viewers. Santa Claus Is Coming to Town (1.7 adults) was flat with last year, and the premiere of TheGreat Christmas Light Fight (1.8 adults) improved on its lead-in.

With all but Mike & Molly (2.0 adults, down 17 percent) and an even Hostages (1.1 adults) in repeats, CBS averaged a 1.3 adults rating and 5.3 million viewers.